Renal apoptosis parallels ceramide content after prolonged ureteral obstruction in the neonatal rat

Obstructive nephropathy, the primary cause of renal insufficiency in infants, is characterized by progressive renal apoptosis. Ceramide is a sphingolipid known to stimulate apoptosis in the kidney. We investigated the effects of unilateral ureteral obstruction (UUO) on endogenous renal ceramide content and apoptosis in neonatal and adult rats. Animals were subjected to UUO or sham operation on the first day of life and were studied 3-28 days later. Adult rats were similarly treated and then studied 3 or 14 days later. In additional neonatal rats, the obstruction was removed after 5 days, with study at 14 or 28 days. Renal ceramide content was measured by diacylglycerol kinase assay, and apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick-end-labeling technique. Renal ceramide content was 50-fold higher in the 3-day neonatal compared with the adult kidney and 10-fold higher in the 7-day neonatal compared with the adult kidney, but there was no additional effect of UUO on ceramide content at these ages. However, after 14 or 28 days UUO in the neonate, renal ceramide was elevated compared with sham or intact opposite kidneys, and renal apoptosis was directly related to ceramide content (r = 0.99, P < 0.001). Moreover, renal ceramide was reduced by relief of obstruction (P < 0.05). There was less apoptosis in the obstructed kidney of the adult than the neonate, and UUO had no effect on ceramide content at 14 days in the adult. We conclude that prolonged UUO (at least 14 days duration) increases endogenous renal ceramide in the neonatal but not the adult rat. It is likely that this contributes to the prolonged renal apoptotic response of the neonatal obstructed kidney.

Vertical profiles of aerosol volume from high-spectral-resolution infrared transmission measurements. I. Methodology

The wavelength-dependent aerosol extinction in the 800-1250-cm(-1) region has been derived from ATMOS (atmospheric trace molecule spectroscopy) high-spectral-resolution IR transmission measurements. Using models of aerosol and cloud extinction, we have performed weighted nonlinear least-squares fitting to determine the aerosol-volume columns and vertical profiles of stratospheric sulfate aerosol and cirrus cloud volume. Modeled extinction by use of cold-temperature aerosol optical constants for a 70-80% sulfuric-acid-water solution shows good agreement with the measurements, and the derived aerosol volumes for a 1992 occultation are consistent with data from other experiments after the eruption of Mt. Pinatubo. The retrieved sulfuric acid aerosol-volume profiles are insensitive to the aerosol-size distribution and somewhat sensitive to the set of optical constants used. Data from the nonspherical cirrus extinction model agree well with a 1994 mid-latitude measurement indicating the presence of cirrus clouds at the tropopause.

Apoptosis parallels ceramide content in the developing rat kidney

Ceramide is emerging as an important hydrophobic sphingolipid involved in cell differentiation and apoptosis. Since apoptosis plays a significant role in cellular remodeling during renal morphogenesis, we measured ceramide content and apoptosis in the fetal (18 days gestation), neonatal (3, 7, and 14 days postnatal), and adult rat kidney. In addition, to determine whether developmental changes in ceramide content are tissue-specific, we compared renal ceramide content with that in lung and liver. Ceramide was measured by the diacylglycerol kinase assay, and apoptosis was determined by the TUNEL technique. Renal ceramide content fell over 100-fold from the fetus to the 7th postnatal day. Renal apoptosis paralleled ceramide content, with a greater than 300-fold decrease in apoptosis from fetal to adult life. Ceramide content of the lung and liver was significantly less than that of the kidney, and changed less with maturation. We conclude that maturational changes in ceramide content are tissue-specific, and that the high rate of apoptosis in the developing kidney may be related to the elevated ceramide content.

Unilateral ureteral obstruction in neonatal rats leads to renal insufficiency in adulthood

BACKGROUND

Although unilateral ureteropelvic junction obstruction is the most common cause of congenital obstructive nephropathy in infants and children, management remains controversial, and follow-up after pyeloplasty is generally limited to the pediatric ages. We have developed a model of temporary unilateral ureteral obstruction (UUO) in the neonatal rat: One month following the relief of five-day UUO, the glomerular filtration rate (GFR) of the postobstructed kidney was normal despite a 40% reduction in the number of glomeruli and residual vascular, glomerular, tubular, and interstitial injury.

METHODS

To determine whether hyperfiltration and residual injury of remaining nephrons leads to progression of renal insufficiency in later life, 31 rats were sham operated or subjected to left UUO at one day of age, with relief of UUO five days later, and were studied at one year of age. GFR was measured by inulin clearance, and the number of glomeruli, tubular atrophy, glomerular sclerosis, and interstitial fibrosis were measured by histomorphometry in sham, obstructed (UUO), and intact opposite kidneys. Intrarenal macrophages and alpha-smooth muscle actin were identified by immunohistochemistry.

RESULTS

Despite relief of UUO, ultimate growth of the postobstructed kidney was impaired. The number of glomeruli was reduced by 40%, and GFR was decreased by 80%. However, despite significant compensatory growth of the opposite kidney, there was no compensatory increase in GFR, and proteinuria was increased. Moreover, glomerular sclerosis, tubular atrophy, macrophage infiltration, and interstitial fibrosis were significantly increased not only in the postobstructed kidney, but also in the opposite kidney.

CONCLUSIONS

Although GFR is initially maintained following relief of five-day UUO in the neonatal rat, there is eventual profound loss of function of the postobstructed and opposite kidneys because of progressive tubulointerstitial and glomerular damage. These findings suggest that despite normal postoperative GFR in infancy, children undergoing pyeloplasty for ureteropelvic junction obstruction should be followed into adulthood. Elucidation of the cellular response to temporary UUO may lead to improved methods to assess renal growth, injury, and functional reserve in patients with congenital obstructive nephropathy.

Hippocampal noradrenergic neurotransmission in concurrent EEG desynchronization and inhibition of penile erection induced by cocaine in the rat

We previously reported that cocaine may induce activation of cortical (cEEG) and hippocampal (hEEG) electroencephalographic signals, concurrent with inhibition of penile erection, via an action on the hippocampal formation. The present study further evaluates the role of noradrenergic neurotransmission at the hippocampal formation in this process, using adult, male Sprague-Dawley rats anaesthetized and maintained by chloral hydrate. Unilateral microinjection of cocaine (100 nmoles) into the hippocampal CA1 or CA3 subfield or dentate gyrus elicited significant activation of both cEEG and hEEG activity. At the same time, the intracavernous pressure (ICP), our experimental index for penile erection, underwent a discernible reduction. Co-administration of equimolar doses (250 pmoles) of prazosin, naftopidil, yohimbine or rauwolscine significantly reversed those effects elicited by cocaine on cEEG, hEEG and ICP. Microinjection unilaterally of equimolar doses (5 nmoles) of norepinephrine, phenylephrine or BHT 933 into the hippocampal formation, similar to cocaine, also induced appreciable cEEG and hEEG excitation, with a simultaneous decrease in ICP. We conclude that cocaine may activate cEEG and hEEG and decrease ICP via noradrenergic neurotransmission, possibly engaging at least alpha(1A/D)-, alpha(2B)- and alpha(2C)-adrenoceptors at the hippocampal formation.

Renal tubulointerstitial injury from ureteral obstruction in the neonatal rat is attenuated by IGF-1

BACKGROUND

The administration of insulin-like growth factor-1 (IGF-1) has been shown to ameliorate the renal injury resulting from ischemic acute renal failure. As there are a number of similarities between acute renal failure and obstructive nephropathy, we examined the effects of IGF-1 on the renal cellular response to unilateral ureteral obstruction (UUO) in the neonatal rat.

METHODS

Forty-five rats were subjected to UUO or sham operation within the first 48 hours of life and received IGF-1 (2 mg/kg/day) or saline for the following three or seven days, after which kidneys were removed for study by morphometry and immunohistochemistry. To determine the effects of UUO on endogenous expression of IGF-1 and its receptor, six additional rats were subjected to UUO or sham operation, and mRNA was measured by solution hybridization.

RESULTS

There was no effect of seven days of UUO on the renal expression of endogenous IGF-1 or its receptor. Moreover, seven days of exogenous IGF-1 did not improve the suppression of nephrogenesis, the delay in glomerular maturation, or the reduction in tubular proliferation induced by ipsilateral UUO. However, in the obstructed kidney, IGF-1 reduced tubular expression of vimentin, apoptosis, and tubular atrophy by 38 to 50% (P < 0.05). In addition, IGF-1 also decreased renal interstitial collagen deposition in the obstructed kidney by 44% (P < 0.05). Following three days of UUO, the administration of IGF-1 also reduced tubular apoptosis (P < 0.05), but did not alter tubular proliferation.

CONCLUSIONS

IGF-1 has a profound salutary effect on the tubular and interstitial response to UUO in early development, without affecting glomerular injury or development. These results suggest that IGF-1 may have therapeutic potential in the management of congenital obstructive nephropathy.

Pilot study with weekly chemotherapy for patients with extensive small cell lung cancer: an Eastern Cooperative Oncology Group Study (PA586)

PURPOSE

Six of the most active chemotherapy agents in small cell lung cancer were administered sequentially in a weekly fashion in an attempt to optimize the dose and the number of agents received over a 12-week period. The purpose of this study was to estimate the efficacy and to characterize the toxicity of this approach.

PATIENTS AND METHODS

Thirty-six patients with extensive-stage small cell lung cancer received weekly treatments with cisplatin and etoposide (weeks 1, 5, and 11), cyclophosphamide (weeks 2, 7, and 10), vincristine (weeks 2, 4, 7, 8, 10, and 12), methotrexate (weeks 3, 6, and 9), and doxorubicin (weeks 4, 8, and 12). Patients achieving a partial response received a second 12-week course. Patients achieving a complete response received prophylactic cranial radiation.

RESULTS

Twenty-nine of the 36 patients completed the initial 12-week program over a median of 16 weeks. Hematologic toxicity was most prominent, with two deaths from sepsis and 31 patients having grade 3 or 4 neutropenia The overall response rate was 85%, with 33% of patients achieving a complete response. The median survival was 10.5 months, and the median time to progression was 8.2 months.

DISCUSSION

This 12-week program, consisting of administration of six active agents for small cell lung cancer, caused significant myelosuppression that resulted in significant treatment delays and dose reductions. Although a high response rate was achieved, the median overall survival of 10.5 months was not significantly longer than expected from other standard two- to three-drug regimens.

Ifosfamide, carboplatin and etoposide (ICE) in metastatic and refractory breast cancer

Twenty-five patients with metastatic breast cancer were treated with ICE after failure of previous chemotherapy. Their median age was 50 years (range 36-73). All but 1 patient had multiple sites of metastases. Nineteen (76%) patients had undergone two or more chemotherapy regimens for metastatic disease prior to ICE. The performance status (PS) of the patients was Eastern Cooperative Oncology Group (ECOG) 0:6; 1:12; 2:5; 3:2. Ifosfamide 1.25 g/m(2) over 3 h D1-3 along with mesna, etoposide 80 mg/m(2) D1-3 and carboplatin 300 mg/m(2) D1 were given every 3 weeks. We observed a partial response in 10 patients (40%, 95% confidence interval 21-62%). The response duration ranged from 1 to 15 months with a median duration of 4.5 months. The survival of all 25 patients ranged from 10 days to 25 months, with a median of 9 months. All 25 patients were evaluable for toxicity. Thirteen patients (52%) experienced grade 4 hematological toxicity, which improved after growth factor support. Four patients had leukopenic fever, 1 had gram-negative sepsis, while 2 had Clostridium difficile enterocolitis and another had herpes zoster reactivation. Four patients (16%) experienced grade 3-4 gastrointestinal (G-I) toxicity. No hepatic or renal toxicity was observed (1 patient had microscopic hematuria). One patient died of G-I bleed, and another patient died at home of undetermined cause. We conclude that ICE is an effective salvage regimen in metastatic and refractory breast cancer, even in heavily pretreated patients, and is a tolerable treatment when used with growth factor.

Radiosensitization with carboplatin for patients with unresectable stage III non-small-cell lung cancer: a phase III trial of the Cancer and Leukemia Group B and the Eastern Cooperative Oncology Group

PURPOSE

To determine whether the administration of carboplatin concurrently with radiation treatment improves survival in patients with inoperable stage III non-small-cell lung cancer.

PATIENTS AND METHODS

Two hundred eighty-three patients with inoperable stage III non-small-cell lung cancer were entered onto a randomized trial by the Cancer and Leukemia Group B and the Eastern Cooperative Oncology Group. Randomization was performed before initiation of any therapy. All patients received an induction chemotherapy program with vinblastine and cisplatin for 5 weeks, followed by 6,000 cGy of radiation therapy over 6 weeks. One hundred thirty-seven patients were randomized to this therapy regimen alone; 146 patients were randomized to receive carboplatin at 100 mg/m2/wk concurrent with the radiation therapy.

RESULTS

The complete response was 18% with concurrent carboplatin versus 10% with radiotherapy alone (P = .101). There was no difference with respect to failure-free survival (10% with carboplatin and 9% with radiotherapy alone) or overall survival (13% with carboplatin and 10% with radiotherapy alone) at 4 years. In patients not receiving carboplatin, the relapse rate was 69% within the field of radiation and 53% in the boost volume. In patients receiving carboplatin, the relapse rate was 59% within the field of radiation and 43% in the boost volume. Patients with cancers more than 70 cm2 in size had significantly poorer survival (P = .01).

CONCLUSION

Carboplatin at the dose and schedule used did not significantly impact on disease control or survival. The relapse rate within the chest remained more than 50%. More effective regimens will be required to impact on local disease control and survival.

Differential participation of hippocampal formation in cocaine-induced cortical electroencephalographic desynchronization and penile erection in the rat

We evaluated the role of the hippocampal formation in cocaine-induced cortical electroencephalographic (EEG) desynchronization and penile erection. Adult, male Sprague-Dawley rats anesthetized and maintained by chloral hydrate were used. Intravenous (1.5 or 3.0 mg/kg) administration of cocaine dose-dependently increased intracavernous pressure (ICP), our experimental index for penile erection. This was accompanied by desynchronization of EEG activity recorded from the somatosensory cortex (cEEG), as represented by a decrease in root mean square (RMS) and an increase in mean power frequency (MPF) values. There was a simultaneous increase in the RMS values, without significant changes in the MPF values of EEG signals recorded from the hippocampal formation (hEEG). In animals that received prior application of 10% xylocaine either intrathecally (i.t.) at the L6-S1 spinal levels or directly into the bilateral hippocampal formation, the RMS values of both cEEG and hEEG signals induced by cocaine (1.5 or 3.0 mg/kg, i.v.) were appreciably reduced, along with a further increase in ICP. Unilateral microinjection of cocaine (15 or 30 microg) into the hippocampal formation elicited discernible excitation of both cEEG and hEEG signals. Intriguingly, the ICP underwent a significant and dose-dependent reduction, which was discernibly antagonized by i.t. application of xylocaine. We conclude that cocaine may effect cortical EEG desynchronization but cause a reduction in ICP via an action on the hippocampal formation.

Phase II study of adozelesin in untreated metastatic breast cancer

Adozelesin is the first of a class of DNA-sequence-selective alkylating agents, the cyclopropa(c)pyrrolo(3,2-e)indol-4(5H)-ones (CPls), that have been shown to have of potent inhibitory properties of DNA synthesis. Based on preliminary data from phase I studies showing clinical activity in patients with breast cancer, we initiated a multicenter phase II study in untreated metastatic breast carcinoma. Adozelesin was administered at a starting dose of 150 microg/m2 as a single 10 min infusion per course, repeated every 4 weeks, for up to 1 year of treatment. It was planned that at least 25 patients should be accrued but the trial was stopped early because of slow accrual and lack of efficacy as demonstrated by the infrequency of objective responses. Seventeen patients were enrolled in this study, only 14 were evaluable, the following responses were observed: one partial response (7%), three stable diseases (22%) and 10 progressive diseases (71%). Myelosuppression was the most frequent adverse event; one patient died of pulmonary complications. We conclude that adozelesin has marginal efficacy in the treatment of metastatic breast cancer at the dosage and schedule used in this study.

Megestrol acetate as a biomodulator

Megestrol acetate is a synthetic analog of progesterone. In general, megestrol acetate exerts its progesterone-like hormonal effect by binding to the progesterone receptor. It has been recognized that megestrol acetate can increase weight and improve some aspects of quality of life in cancer patients and in patients with the acquired immunodeficiency syndrome. This effect occurs in patients with or without concurrent chemotherapy or radiotherapy, through an as yet unknown mechanism. Recently, megestrol acetate has been shown to reverse, at least partially, multidrug resistance to doxorubicin and/or vincristine in cancer cell lines. This potentially beneficial effect has not yet been studied in clinical trials. This biological activity is thought to be mediated through the unique binding of megestrol acetate to p-glycoprotein. At least in vitro megestrol acetate can also enhance the cytotoxic effect of these two chemotherapeutic agents in some MDR-nonexpressing cell lines. These findings suggest that megestrol acetate deserves further preclinical and clinical studies to evaluate its potential role of enhancing cytotoxicity of chemotherapy and improving the quality of life of cancer patients.

Participation of hippocampal formation in negative feedback inhibition of penile erection in the rat

Detailed information on how the central nervous system regulates penile erection, particularly the inhibitory aspect, is sparse. We observed in Sprague-Dawley rats anesthetized and maintained with chloral hydrate that administration of papaverine (400 microg) directly into the corpora cavernosum of the penis produced an increase in intracavernous pressure (ICP). This elicited experimental index for penile erection was accompanied by a transient increase in the root mean square values, concurrent with a shift in the contribution of Theta (increase) and delta (decrease) power to the hippocampal electroencephalographic (hEEG) activity. Reversal blockade of these hEEG responses with xylocaine, given either intrathecally at the L6-S1 spinal levels or unilaterally to the hippocampal formation, significantly heightened and prolonged the ICP response. Pretreatment with xylocaine by itself, however, did not alter appreciably the baseline ICP or hEEG activity. These results suggest the presence of a novel negative feedback inhibitory mechanism in the hippocampal formation, which is triggered by ascending sensory inputs initiated by tumescence of the penis during normal erectile processes.

Induction chemotherapy of dibromodulcitol, Adriamycin, vincristine, tamoxifen, and Halotestin with methotrexate in metastatic breast cancer: an Eastern Cooperative Oncology Group Study (E1181)

Patients who have metastatic breast cancer are seldom curable. Chemotherapy given by conventional doses and schedules generally produces complete remissions in 10% to 20% of patients. This study sought to determine 1) whether a combination of dibromodulcitol, Adriamycin, vincristine, tamoxifen, Halotestin, and methotrexate with leucovorin rescue (DAVTHML) can produce a complete remission rate of 50%; and 2) the toxicity of this combination in patients with chemotherapy-naive metastatic breast cancer. Patients were treated with six 28-day cycles of DAVTHML induction chemotherapy consisting of dibromodulcitol, 135 mg/m2 perorally days 1 to 10; Adriamycin 45 mg/m2 intravenously day 1; vincristine, 2 mg intravenously day 1; tamoxifen and Halotestin, 20 mg perorally daily; methotrexate, 800 mg/m2 intravenously days 15 and 22; and leucovorin, 15 mg/m2 perorally every 6 hours for 9 doses, starting 4 hours after methotrexate. After induction, patients who had stable disease or a partial response were treated with a cyclophosphamide, methotrexate, and 5-fluorouracil-based regimen (CMF). Patients in complete remission were treated with three additional cycles of DAVTHML after achieving complete remission and then observed off therapy until relapse, when DAVTHML was to be given again. Fifty-eight patients were included in this study. During induction, 26% of eligible patients experienced a complete remission; overall response rate was 80%. The median time to treatment failure and the median survival time of eligible patients was 11.1 and 24.0 months, respectively. This did not change significantly when all the patients were included in the evaluation. The 3-year and 5-year survival rates were 37% and 11%, respectively. Ninety percent of the eligible patients experienced grade III or IV toxicity. They were leukopenia (75%), anemia (20%), thrombocytopenia (20%), and vomiting (17%). No lethal toxicity was documented during therapy; however, 1 patient later died of myelodysplastic syndrome induced by dibromodulcitol. The overall response and complete remission rates from our study were encouraging. The toxicity of DAVTHML was tolerable, with the exception of myelodysplastic syndrome from dibromodulcitol. The concept of using mid-cycle nonmyelosuppressant agents to increase complete remission rate is feasible.

A randomized phase II trial of echinomycin, trimetrexate, and cisplatin plus etoposide in patients with metastatic nonsmall cell lung carcinoma: an Eastern Cooperative Oncology Group Study (E1587)

BACKGROUND

Patients with metastatic nonsmall cell lung carcinoma (NSCLC) usually have a poor prognosis. A chemotherapy regimen containing cisplatin is commonly used for symptom palliation. Echinomycin is a potent bifunctional intercalator of double-strand DNA; trimetrexate is a new derivative of methotrexate and is active against methotrexate-resistant tumor cells in vitro.

METHODS

The Eastern Cooperative Oncology Group conducted a randomized Phase II study. Eligible patients were assigned to receive echinomycin 1200 microg/m2 by intravenous (i.v.) infusion over 30-60 minutes once a week for 4 weeks, repeated every 6 weeks; trimetrexate 12 mg/m2 i.v. bolus on Days 1-5 every 3 weeks, or 8 mg/m2 i.v. bolus on Days 1-5 for patients who had prior radiation to greater than 30% of their bone marrow; or cisplatin 60 mg/m2 i.v. on Day 1 and etoposide 120 mg/m2 i.v. on Days 1-3 every 4 weeks. Patients were evaluated before each cycle for tumor response, toxicity, and quality-of-life measurements.

RESULTS

One hundred thirty-six patients were entered on the study, and 118 were evaluable for toxicity and response. The response rates were 16%, 5%, and 5% in patients treated with cisplatin and etoposide, echinomycin, and trimetrexate, respectively. There were no complete responses. The median survival was 37.9, 24.3, and 28.0 weeks for patients who received cisplatin and etoposide, echinomycin, and trimetrexate, respectively. Although cisplatin and etoposide appeared to give better therapeutic results, the response rate or survival did not reach statistical significance. This may have been due to inadequate sample size. Neither did quality-of-life measurement show any significant differences among treatments.

CONCLUSIONS

Echinomycin and trimetrexate had minimal antitumor activity in patients with metastatic NSCLC: Response rate and survival remained poor in all three treatment arms. Patients should be encouraged to participate in clinical trials so that more effective therapy can be identified.

Recent advances with chemotherapy for NSCLC: the ECOG experience. Eastern Cooperative Oncology Group

Management of disseminated non-small-cell lung cancer has changed over the past 10 years. Newer agents, such as vinorelbine (Navelbine) and paclitaxel (Taxol), have been shown to modestly improve survival in patients with advanced disease when administered in conjunction with cisplatin (Platinol). Compared with older regimens consisting of cisplatin and a Vinca alkaloid or a podophyllotoxin, the newer regimens yield a 10- to 15-week improvement in median survival and an additional 10% to 15% in 1-year survival. Based on these results derived from randomized trials, it appears that metastatic non-small-cell lung cancer patients with good performance status should be treated with regimens containing either vinorelbine or paclitaxel in conjunction with cisplatin.

Engineering a human bone marrow model: a case study on ex vivo erythropoiesis

Bone marrow, with its intricate, three-dimensional tissue structure facilitating cell-cell interactions, provides a microenvironment supporting the production of hundreds of billions of multilineal blood cells everyday. We have developed a three-dimensional bone marrow culture system in which marrow cells are cultured in a reactor packed with porous microspheres. The culture supports a three-dimensional growth configuration and multilineal hemopoiesis mimicking the bone marrow in vivo. We studied ex vivo human erythropoiesis using the three-dimensional culture system. The system sustained extensive erythropoiesis at low erythropoietin concentrations (0.2 U/mL), plus stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor, and insulin-like growth factor-I. Erythroid cell production lasted for more than 5 weeks, and the percentage of erythroid cells in the nonadherent cell population was approximately 60%. Flow cytometric analysis using cell surface markers specific for erythroid cells (CD71 and glycophorin-A) indicated that the culture produced early, intermediate, and late erythroid cells. As the culture progressed, the erythroid cell population shifted gradually toward mature cell types. When compared to the three-dimensional culture, the traditional flask cultures failed to support extensive erythropoiesis under the same conditions. This indicates that the three-dimensional bone marrow culture system provides a microenvironment conducive to erythropoiesis under more physiological conditions and is a better bone marrow model.

The potential role of topotecan in the treatment of advanced breast cancer

Despite the rational use of hormonal, surgical, radiotherapeutic, and chemotherapeutic interventions, metastatic breast cancer represents a historically incurable disease and is currently one of the leading causes of cancer-related death in women. Survival rates in patients with metastatic breast cancer vary with location and type of metastasis, but virtually all will relapse. Standard cytotoxic therapies for the treatment of metastatic breast cancer remain unsatisfactory; thus, new active agents can be a valuable option for many patients. Topotecan (Hycamtin; SmithKline Beecham Pharmaceuticals, Philadelphia, PA), a topoisomerase I inhibitor, currently is being assessed in the treatment of metastatic breast cancer. Preliminary results from preclinical and phase I trials suggest topotecan is active against breast cancer. Results of ongoing phase II trials thus far suggest that topotecan may be effective in stabilizing disease and prolonging time to relapse. Further studies are needed to determine whether topotecan will prove to be a valuable new option in the treatment of metastatic breast cancer.

Dose-escalation study of weekly 1-hour paclitaxel administration in patients with refractory cancer

To evaluate the safety and efficacy of weekly low-dose paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in patients with refractory cancer, participating subjects received standard prophylactic medication followed by intravenous paclitaxel once a week for 3 weeks every 4 weeks. The 50-mg/m2 starting dose was increased by 10 mg/m2 for every five patients, as long as no dose-limiting toxicity had occurred in more than two of five patients treated at the preceding level. Eligibility criteria included metastatic and refractory malignant disease; an Eastern Cooperative Oncology Group performance status of 0, 1, or 2; and adequate hematologic, hepatic, and renal functions. Of 30 patients treated and evaluable for toxicity, 25 were evaluable for response. The majority of patients tolerated the treatment very well. In a total of 114 cycles, the worst toxicities observed were leukopenia (one grade 4, two grade 3), granulocytopenia (one grade 3, one grade 4), anemia (one grade 3, two grade 2), and infection (one grade 5, one grade 3). Three patients had grade 2 gastrointestinal toxicity and three had grade 1 peripheral neuropathy. Only one dose-limiting toxicity, at 100 mg/m2, has occurred. This patient died of bilateral pneumonia with neutropenia. We have observed partial responses in seven of 12 patients with breast cancer and three of eight with non-small cell lung cancer. The study remains open at the current dose level of 100 mg/m2/wk. Weekly low-dose paclitaxel is well tolerated and efficacious. Further phase II studies are warranted, to continue evaluation of this schedule of paclitaxel either alone or in combination with other drugs active in paclitaxel-responsive diseases.

Pharmacokinetics of intrapericardial administration of 5-fluorouracil

A 30-year-old patient with metastatic breast adenocarcinoma was diagnosed as having a malignant pericardial effusion.

METHODS

The patient was treated with two courses of 200 mg 5-fluorouracil (5-FU) followed by 20 mg cisplatin 5 h later directly infused into the pericardial space through a catheter. The drug levels of the 5-FU were monitored during the second treatment. The half-life of 5-FU in the pericardial space was 168.6 min with a concentration of 0.113 mg/ml still detected at 5 h. The area under the curve (AUC) was estimated to be 4.739 mg h/ml. The plasma concentrations of 5-FU ranged from 0.022 to 0.04 mg/ml throughout the infusion.

RESULTS

There was no significant change in the patient's blood counts or chemistry profile. She did not experience any side effects during the treatment. A pericardial window was performed 2 days later when balloon pericardiectomy was unsuccessful. The patient eventually succumbed to her disease 4 months later, but without evidence of pericardial effusion.

CONCLUSIONS

We conclude that pericardial infusion of 5-FU allowed a high concentration of 5-FU to be achieved within the pericardial sac with a greatly increased half-life over that of systemic 5-FU treatment (168 min vs 6-20 min), and with little systemic toxicity.

Concurrent elicitation of electroencephalographic desynchronization and penile erection by cocaine in the rat

It is well-known from animal and human studies that, as a central nervous stimulant, cocaine induces electroencephalographic (EEG) desynchronization. Cocaine also purportedly increases sexual behavior as an aphrodisiac. Whether the effects of cocaine on EEG activity and penile erection are mechanistically linked, however, remains to be fully elucidated. We evaluated whether this link exists, based on simultaneous recording of EEG signals from the somatosensory cortex and intracavernous pressure (ICP, as experimental index for penile erection) in adult, male Sprague-Dawley rats. Under intraperitoneal chloral hydrate anesthesia (400 mg/kg, i.p.), both intravenous (i.v.) and intracavernous (i.c.) administration of cocaine (1.5 or 3.0 mg/kg, and 75 or 150 micrograms) dose-dependently induced discernible EEG desynchronization, as represented by a decrease in root mean square and an increase in mean power frequency values, and an increase in ICP. However, the same administration of cocaine in animals under pentobarbital sodium anesthesia (50 mg/kg, i.p.) failed to significantly affect EEG activity, despite an appreciable dose-dependent elevation in ICP. On the other hand, intracerebroventricular administration of cocaine (7.5, 15, or 30 micrograms) induced significant EEG activation without affecting ICP. I.c. application of papaverine (400 micrograms) elicited a discernible increase in ICP, but failed to evoke EEG desynchronization. These results suggest that the concurrent EEG desynchronization and penile erection elicited by cocaine may take place without a mutually causative relationship.

Recombinant human interferon-beta (rHuIFN-beta) and radiation therapy for inoperable non-small cell lung cancer

Fifteen patients with stage II, IIIA, and IIIB non-small cell lung cancer (NSCLC) received subcutaneous (s.c.) recombinant, glycosylated, human interferon-beta 1a (Rebif; rHuIFN-beta 1a) on each day of conventionally fractionated radiation therapy (RT) given in 2.0 Gy fractions to 60 Gy in 6 weeks. The rHuIFN-beta 1a was generated in CHO cells by recombinant DNA technology and is identical to natural IFN-beta produced by fibroblasts in primary sequence and glycosylation. Cohorts of three patients each were treated with escalating doses of rHuIFN-beta 1a: 1.5, 3, 6, 12, and 24 MIU/m2 per treatment day. Acute toxicity was assessed according to modified WHO criteria; late toxicity was graded using RTOG late toxicity criteria. The maximum tolerated dose (MTD) of rHuIFN-beta 1a was defined as the dose level immediately below that in which dose-limiting toxicity occurred in > or = two of six patients. Immunomodulatory effects and antigenicity of rHuIFN-beta 1a were assessed by 2-5A synthetase, beta 2-microglobulin, and neopterin levels and by measurement of anti-rHuIFN-beta antibodies, respectively. Fourteen of fifteen patients experienced grades 1-3 acute (early) toxicity (< or = 90 days), which was primarily gastrointestinal: dysphagia/esophagitis (14/15), nausea/vomiting (12/15), anorexia (7/15), and liver transaminasemia (6/15). One of three patients treated with 24 MIU/m2 per treatment day (total rHuIFN-beta 1a dose 672 MIU) died of complications secondary to pneumonia, sepsis, adult respiratory distress syndrome (ARDS), and radiation pneumonitis. Twelve patients were evaluable for late toxicity (> 90 days). Maximum toxicity was grade 0 in five patients, grade 1 in four patients, and grade 5 in one patient (radiation pneumonitis). Clinical responses from the combination were 1/15 CR, 6/15 PR, 6/15 stable disease, and 1/15 progressive disease. The MTD of rHuIFN-beta 1a has been estimated at 12 MIU/m2 per treatment day when given daily during conventional RT to 60 Gy in 6 weeks. Biologic response by rHuIFN-beta 1a alone was reflected by significant and dose-related increases in 2-5A synthetase, beta 2-microglobulin, and neopterin. Radiation therapy alone had no effect on these immune response parameters and did not diminish their augmentation by rHuIFN-beta 1a. There was no association of biologic modulation with clinical response or survival.

Remote sensing of the Earth's atmosphere from space with high-resolution Fourier-transform spectroscopy: development and methodology of data processing for the Atmospheric Trace Molecule Spectroscopy experiment

The methodology of spectroscopic remote sensing with high-resolution Fourier-transform spectra obtained from low Earth orbit by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment is discussed. During the course of the Atmospheric Laboratory for Applications and Science (ATLAS) shuttle missions (1992-1994) a flexible, yet reproducible, retrieval strategy was developed that culminated in the near-real-time processing of telemetry data into vertical profiles of atmospheric composition during the ATLAS-3 mission. The development, evolution, robustness, and validation of the measurements are presented and assessed with a summary comparison of trace-gas observations within the Antarctic polar vortex in November 1994.